Turn M4A files into AIFF in a couple of clicks. M4A is an MP4 container holding AAC or ALAC audio; AIFF is Apple's uncompressed audio counterpart to WAV. The conversion is lossless — every pixel, sample or byte in the source is preserved.
Drop your files here
M4A files (.m4a, .m4b) · up to 300 MB each
or paste files from your clipboard
Ready when you are
Drop a M4A file above and FileTools360 will turn it into AIFF — right here on your device, without uploading anything.
Drag them onto the drop area, choose them from your device, or paste them from your clipboard. You can queue several at once. Nothing is sent anywhere — the file stays on this device.
The defaults suit most people. Open Advanced to control bitrate, sample rate and channels.
Press Convert. Everything happens on your own device — nothing is uploaded. Download files one by one, or grab them all as a ZIP.
Privacy, in plain words
What “uploaded” normally means. On most online converters, pressing the button copies your file across the internet onto a computer owned by that website. That copy is what the word “upload” means, and it is the part nobody explains.
What happens instead. This site does not do it. There is no server here that receives files, so your M4A file is read, converted and handed back by the browser you are using right now. It never travels — so there is no copy to store, read, leak or hand over.
Check it yourself in ten seconds
Turn off your Wi-Fi after this page has loaded, then convert a file anyway. It still works, because everything needed is already on your device.
The longer explanation of how this works, and the full detail of what is and is not stored on the privacy page.
An audio file is a conversation. Transcribed by machine — which is cheap now — it becomes searchable text about whoever was speaking. It matters more than it sounds, because of what audio files usually are:
Meeting audio
internal discussion, named people, unannounced decisions
Unreleased music
work whose commercial value depends on control of the master
Call recordings
both sides of a conversation, often legally sensitive
Interviews
a source's voice is identifying even when the name is not said
A file that is never sent cannot be kept, leaked, subpoenaed or used to train anything. That is a property of how this works, not a promise about how carefully it is run.
M4A is an MP4 container holding only audio — usually AAC, sometimes Apple Lossless. The extension exists mainly so players know not to look for a video track.
AIFF is Apple's uncompressed audio format, functionally equivalent to WAV but with better metadata support and big-endian byte order.
The two formats solve different problems, which is why converting between them involves trade-offs rather than a straight upgrade.
| Property | Source | Target |
|---|---|---|
| Compression | Lossy or lossless | Uncompressed |
| Introduced | 2001 | 1988 |
| Browser support | Very good, especially on Apple platforms. | Strong on Apple, decent elsewhere. |
People make this switch when they run into the limits of M4A: you need certainty that any device will play it. AIFF is the better fit when audio production on a Mac.
Be aware of the size trade-off: AIFF is uncompressed, so expect the converted file to be considerably larger than the M4A you started with.
Both formats store the content without discarding data, so this conversion preserves it exactly. The file size may change because the two formats compress differently, but the content itself is unaffected.
On every sample measured, the AIFF came out larger — 5.5× larger at best and 5.6× larger at worst.
| Sample | M4A in | AIFF out | Change |
|---|---|---|---|
| An easy clipThe compressible end of the range — a clean tone, or a moving test pattern — where a codec does its best work. | 31.1 KB | 174 KB | 5.6× |
| A hard clipThe other end — pink noise, or dense video grain. Close to incompressible by design, and the worst case for every codec. | 31.9 KB | 174 KB | 5.5× |
Produced by this site's own converter. The same code that runs in your browser, at the same default settings, so these are the bytes you would download.
Samples are generated from a fixed seed rather than taken from real photographs or documents, so the corpus is reproducible and carries no licensing question — and so the numbers predict the shape of your result rather than its exact size. Measured 2026-10-01. The method, and the command that regenerates every figure on this page, are on the how it works page.
Source
MP4 container holding AAC or ALAC audio.
Target
Apple's uncompressed audio counterpart to WAV.
The output is a lossless container, but the audio inside it was already compressed. You get a bigger file, not better sound.
Good to know
Runs entirely in your browser
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